The invention relates generally to agricultural vehicles that use tracks. More particularly it is directed to structures for adjusting the lateral spacing of tracked suspensions in such vehicles.
Agricultural vehicles using tracks instead of wheels are difficult to adjust. Changing the lateral spacing between the tracks may require substantial disassembly of the tracked suspensions. It would be beneficial to provide a tracked suspension that is more easily adjustable to vary the lateral spacing of the tracks. It is an object of this invention to provide such a suspension.
In accordance with a first embodiment a rear suspension for a tracked vehicle is provided including a differential case, a differential pinion gear for receiving rotational power from a prime mover, a driving gear gearingly coupled to and driven by the differential pinion, a differential carrier fixed to the driving gear, at least two pinion gears coupled to the differential carrier to permit relative rotation with respect to the differential carrier, two laterally opposed side gears adapted to rotate about a rotational axis and supported by the differential carrier for relative rotation with respect to the differential carrier and wherein the at least two pinion gears are adapted to drive the two laterally opposed side gears, first and second spur gears rotatable about the rotational axis wherein each of said first and second spur gears is coupled to and driven by a respective one of the two laterally opposed side gears, third and fourth spur gears with respective second and third rotational axes, the third and fourth gears engaged to and driven by the first and second spur gears, respectively, wherein the second and third rotational axes extend across a top portion of the differential case, and first and second splined drive axles each having an inner and an outer end and wherein the first drive axle splines are slidingly supported within and driven by the third spur gear and the second drive axle splines are slidingly supported within and driven by the fourth spur gear. The first, second, third and fourth spur gears may be supported within the differential case. Each of the third and fourth spur gears may be disposed adjacent to openings in the differential case to permit the drive axles to pass through the differential case. The third and fourth spur gears may also include splines disposed outboard of the third and fourth spur gear teeth. The outer end of the first and second drive axle may be coupled to a drive wheel for driving an endless track.
In accordance with a second embodiment, a rear suspension is provided, having a differential case, a differential pinion gear for receiving rotational power from a prime mover, a differential gear set supported within the differential case, first and second spur gears rotatable about the rotational axis disposed on opposing sides of the differential gear set and differentially driven by the differential gear set, third and fourth spur gears rotationally engaged with and driven by the first and second spur gears, respectively, wherein the rotational axes of the third and fourth spur gears lie in a horizontal plane and are substantially parallel to each other, and first and second splined drive axles each having an inner and an outer end and wherein first drive axle splines are slidingly supported within and driven by the third spur gear and second drive axle splines are slidingly supported within and driven by the fourth spur gear. The first and second drive axle splines are preferably of sufficient length and the rotational axes are sufficiently far apart to permit the inner ends of the first and second drive axles to be inserted through the third and fourth spur gears, respectively, and to lie side-by-side without axle-to-axle interference. The third and fourth spur gears may be disposed within and rotationally supported by the differential case. The suspension may further include first and second drive wheels coupled to and rotating coaxially with the outer ends of the first and second drive axles, respectively. The suspension may further include first and second endless tracks wrapped about and driven by first and second drive wheels, respectively. The first drive axle may include first inner and outer flexible couplings, the first inner flexible coupling being disposed in the first drive axle adjacent to the third spur gear, and the first outer flexible coupling being disposed in the first drive axle adjacent the first drive wheel, and wherein the second drive axle includes second inner and outer flexible couplings, the second inner flexible coupling being disposed in the second drive axle adjacent to the fourth spur gear, and the second outer flexible coupling being disposed in the second drive axle adjacent the second drive wheel.
In accordance with a third embodiment of the invention, a tracked agricultural vehicle is provided, having a frame, an engine coupled to the frame, a first differential case including a first differential gear set and first and second spur gears driven by the differential gear set wherein the first and second spur gears are disposed on opposing sides of the differential case and have substantially parallel and horizontal rotational axes that are disposed above the differential gear set, first and second drive axles slidingly engaged and coaxial with the first and second spur gears and extending laterally away from the vehicle on opposing sides of the vehicle, first and second drive wheels fixed to an outer end of the first and second drive axles, respectively and sharing a common rotational axis with the first and second drive axles, first and second tracks each having a wrapped portion wrapped around the third and fourth drive wheel, respectively, and further having a forwardly extending portion extending from the wrapped portion downward and forward and away from its respective drive wheel, and further having a rearwardly extending portion extending from the wrapped portion downward and forward and away from its respective drive wheel. The vehicle may also include a second differential case including a second differential gear set and third and fourth spur gears driven by the differential gear set wherein the third and fourth spur gears are disposed on opposing sides of the differential case and have substantially parallel and horizontal rotational axes disposed above the differential gear set, third and fourth drive axles slidingly engaged and coaxial with the third and fourth spur gears and extending laterally away from the vehicle on opposing sides of the vehicle, third and fourth drive wheels fixed to an outer end of the third and fourth drive axles, respectively, and sharing a common rotational axis with the third and fourth drive axles, third and fourth tracks having a wrapped portion wrapped around the third and fourth drive wheel, respectively; and further having a forwardly extending portion extending from the wrapped portion downward and forward and away from its respective drive wheel, and further having a rearwardly extending portion extending from the wrapped portion downward and forward and away from its respective drive wheel. The first differential case may be disposed at the front of the vehicle and the second differential gear box may be disposed at the rear of the vehicle. The first and second drive axles may also include at least a first and second flexible coupling disposed in the first and second drive axles, respectively. The first and second drive axles may include at least a first and second flexible coupling disposed in each of the first and second drive axles, respectively, wherein the first flexible couplings are disposed in each of the first and second drive axles adjacent to the first and second spur gears, and the second flexible couplings are disposed in each of the first and second drive axles adjacent to the drive wheels.
Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.